This invention relates to hydrogen storage systems and more particulary to a solid-state hydrogen storage system.
Hydrogen gas is attractive as a fuel for use in transportation systems because it has the highest density of energy per unit weight of any fuel and is non-polluting. Present methods of storing hydrogen are suitable for industrial uses but are inappropriate for use in transportation systems. Accordingly, systems for storing and pumping hydrogen are an important subject of research and development.
Hydrogen storage in solid materials, referred to as solid state storage hereinafter, is being developed as an alternative to more standard methods of storage such as storage in compression tanks. A great advantage of solid-state storage is the achievement of storage densities several times that of liquid hydrogen. Additionally, hydrogen stored in a solid is relatively safe to handle without the normal problems of fire and explosion.
Heretofore, most of the solid materials utilized for hydrogen storage have been crystalline solids. A major problem with those materials has been the high pressure required to overcome the surface energy barrier of the material in order to force hydrogen into the bulk thereof. Additional problems with crystalline materials include the requirement of high temperatures for discharging stored hydrogen from the solid materials and surface poisoning in the presence of atmospheric gases that reduces absorption and discharge rates.